Inline item editing on details pages; fix Stripe receipt_email

Allow description, quantity, and price to be edited inline on Quote,
Job, and Invoice details pages without re-opening the wizard. Coating
and prep service rows remain read-only by design. Invoice editing is
gated to Draft/Sent/Overdue statuses; totals update live in the DOM.

Remove receipt_email from Stripe PaymentIntent creation so customers
can use any email they choose at checkout — Stripe validates format
and sends the receipt to whatever the customer enters in the Payment
Element, eliminating the risk of a stored email mismatch blocking a
payment from processing.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Web/Controllers/PaymentController.cs

@@ -127,8 +127,6 @@ public class PaymentController : Controller
             return BadRequest(new { error = "Invalid payment amount." });
 
         var surcharge = CalculateSurcharge(request.Amount, company!);
-        var customer = await _context.Customers.AsNoTracking()
-            .FirstOrDefaultAsync(c => c.Id == invoice.CustomerId);
 
         var (success, clientSecret, paymentIntentId, stripeError) =
             await _stripeConnect.CreatePaymentIntentAsync(
@@ -136,7 +134,6 @@ public class PaymentController : Controller
                 invoiceTotal: request.Amount,
                 surchargeAmount: surcharge,
                 currency: "usd",
-                customerEmail: customer?.Email ?? string.Empty,
                 invoiceNumber: invoice.InvoiceNumber,
                 invoiceId: invoice.Id);
 
@@ -296,7 +293,6 @@ public class PaymentController : Controller
 
         var depositAmount = Math.Round(quote!.Total * (quote.DepositPercent / 100m), 2);
         var surcharge = CalculateSurcharge(depositAmount, company!);
-        var customerEmail = quote.Customer?.Email ?? quote.ProspectEmail ?? string.Empty;
 
         var (success, clientSecret, paymentIntentId, stripeError) =
             await _stripeConnect.CreateDepositPaymentIntentAsync(
@@ -304,7 +300,6 @@ public class PaymentController : Controller
                 depositAmount: depositAmount,
                 surchargeAmount: surcharge,
                 currency: "usd",
-                customerEmail: customerEmail,
                 quoteNumber: quote.QuoteNumber,
                 quoteId: quote.Id);